help for the t he reason for resistance of mosfet change ?

[poweric]

hi i have burn in a AC-DC IC (integrate the MOSfet ), while working in the high temperature for 12 hours, the resistance between the drain and source of MOSFET become 5M, the the resistance between the source drain and sourec of MOSFET become 300K, the ininal values for these are infinite and 11M, then it canbe work.

after that the above IC is place in the hotroom (temp=175) for 4 hours not work condicitons , The Resistance between the drain-source and source-drain become the infinite and 11M , then it can work now.

we also find if IC is place in the hotroom for 4 hours first , then working in the high temprature for 12 hours , the resistance dont change any.

thank you for help

 

[kabiru]

Hi,the reason is when ever there is change in tempreture in a material,it's resistance also varies but this depend on the type of material been used for the fabrication of the chip,when you cheak into the datasheet of any semiconductor you will see how it's resistance,current or voltage varies with temprature,therefore for a proper working of a chip that responce to high temprature a cooling system need to be added to it to ensure proper functioning of the chip.

 

[poweric]

thank for help
but i want to know this can be depend on the IC fault or the pack fault

can you also give some advise to check the fault and change the fault

 

[kabiru]

If you ic work fine at room temprature, then you should now that the ic would not work fine at higher temprature but simply download it's datasheet's and cheak it's maximum temprature of operation and make sure you dont go beyond that temp,and if you can provide proper cooling system for it then it should work fine,and for the replacement you need to be sure if it's the ic that goes bad or else you will keep on changing many component their.:idea:

 

[poweric]

oh
i am sorry to say this IC is my company productions,
now it is test by some costorm